JP2001079638A - Hypoid gear for differential and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manufacturing method of a hypoid gear for differential, capable of reducing a production cost and improving gear face strength. SOLUTION: After a round bar stock W1 is upset forged to form a first preform W2 of a disk shape, a second preform W3 of a bottomed ring shape smaller in diameter and thicker than a final product is formed, by blanking the bottom part, a bottomless ring shape third preform W4 is formed, and then by subjecting the preform to descaling, reheating and rolling, a forth preform W5 having a rough product shape slightly smaller and thicker than the final product is manufactured, a fifth preform W6, in which a hypoid teeth are toothed by oscillation form rolling, is formed, further by subjecting the preform to annealing, descaling and then blanking the inner burr in forming, cold coining, a hypoid ring gear for differential W7 is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hypoid ring gear for a differential of an FR vehicle and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of this type of hypoid ring gear for differentials (hereinafter referred to as a hypoid ring gear), as shown in FIG. 6, a round bar material (A1) is heated and upset and forged. To form a disk-shaped first intermediate product (A2), forging the first intermediate product (A2) by die forging, and forming a bottomed annular second intermediate product (A) having substantially the same diameter as the final inner and outer diameters.
3) to form the bottom (A) of the second intermediate product (A3).
3 ') is punched out to form a bottomless annular third intermediate product (A4). After normalizing this third intermediate product (A4) by shot blasting, the third intermediate product (A4) is subjected to NC lathe or the like. Turning to form a fourth intermediate product (A5) of a rough product shape,
The fourth intermediate product (A5) was subjected to rough cutting by a Gleason gear cutting machine for rough machining, and then subjected to gear cutting and finishing by a Gleason gear cutting machine for finishing to cut and form hypoid teeth (g). The final product (A6) is formed.

[0003]

A conventional method for manufacturing a hypoid ring gear is disclosed in Japanese Patent Application Laid-Open No. H11-27138.
Directly forging the second intermediate product (A3) with an annular bottom and having substantially the same inner and outer diameters as the final product (A6), requires a large forging press machine. In order to cut and form hypoid teeth (g), two expensive Gleason gear cutters are also required, and there is a disadvantage that the equipment cost is very high. In addition, since the hypoid teeth (g) are formed by cutting, the machining allowance (turning amount and gear cutting amount) in the cutting process is increased, and not only the material yield is deteriorated, but also the cutting time is reduced. However, there is a disadvantage that the running cost is long and the running cost is high.

Further, in the hypoid ring gear manufactured by the conventional manufacturing method, the hypoid tooth (g) is cut by cutting, and the metal flow of the hypoid tooth (g) is cut by a cutter to form a tooth surface. Strength decreases. Therefore, a large hypoid ring gear is required to transmit a large load, and there is a drawback that the differential is enlarged accordingly.

The present invention has been proposed in view of the above-mentioned drawbacks of the prior art, and aims at reducing equipment and running costs, minimizing manufacturing costs, and reducing the tooth surface of hypoid teeth. An object of the present invention is to provide a hypoid ring gear for differential which can improve strength and a method of manufacturing the same.

[0006]

In order to achieve the above object, the present invention comprises the steps of upsetting and forging a round bar material heated to a predetermined temperature to form a disc-shaped first intermediate product; The first intermediate product is die-forged, and has a smaller diameter than the final inner and outer diameters, and a bottomed annular second thickness which is thicker in the axial direction than the final axial thickness.
Forming an intermediate product; and punching a bottom portion of the second intermediate product to form a bottomless annular third intermediate product having a smaller diameter than the final inner and outer diameters and an axial thickness greater than the final axial thickness. Forming step, shot blasting the third intermediate product to remove scale, reheating to a predetermined temperature, and ring-rolling the same to make the axial thickness slightly smaller than the final inner and outer diameters. Forming a fourth intermediate product having a slightly larger product thickness than the axial thickness of the intermediate product, and forming the fifth intermediate product by shaping and rolling the fourth intermediate product to form a hypoid tooth. After normalizing and removing scale by normalizing shot blasting the fifth intermediate product, punching out and cold-coining the inner burr of the fifth intermediate product formed at the time of tooth forming and forming a final product. Process and the differential Poidoringugya are those that were produced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a process explanatory view showing a method for manufacturing a hypoid ring gear according to the present invention. In the method of manufacturing a hypoid ring gear according to the present invention, first, a round bar material (W1) cut to a fixed size is heated to a predetermined temperature (for example, 1200 ° C.) by an induction heater, and is upset and forged by a forging press machine. To form a disk-shaped first intermediate product (W2). Next, the first intermediate product (W1) is die-forged by a forging press, and has a smaller diameter than the final inner and outer diameters and a thickness in the axial direction larger than the final axial thickness. An intermediate product (W3) is formed. Next, the second intermediate product (W
The bottom (W3 ') of 3) is punched out by a forging press, and has a smaller diameter than the final inner and outer diameters and a thickness in the axial direction larger than the final axial thickness. ) Is formed. Next, after the third intermediate product (W4) is shot-blasted and scale is removed, the third intermediate product (W4) is heated to a predetermined temperature (for example, 900 to 900) by an induction heater.
950 ° C.), and the resulting product is ring-rolled by a rolling machine, and has a slightly smaller diameter than the final inner and outer diameters and a slightly thicker axial thickness than the final axial thickness. An intermediate product (W5) is formed. Next, the fourth intermediate product (W5) is oscillated and rolled by an oscillating rolling machine to form a fifth intermediate product (W6) in which the hypoid teeth (G) are formed. Next, after normalizing and descaling the fifth intermediate product (W6) by normalizing shot blasting, the fifth intermediate product (W6) formed at the time of tooth forming by a punching machine.
The final product (W7) is formed by punching and cold coining the burrs (W6 ').

The above-mentioned forging press machine is configured so that a plurality of punches and dies are installed at equal intervals, and the forming operation thereof is performed in synchronism with each other, and the forging target is moved to a processing position of each punch and die by a transfer feeder. It is configured to supply sequentially. That is, as shown in FIG. 2, a round bar material (W) heated to a predetermined temperature by an induction heater (1) is used.
1) Upset forging with an upsetting punch (2) and a die (3) to form a disc-shaped first intermediate product (W2).
The intermediate product (W2) is die-forged with a punch (4) and a die (5) smaller in diameter than the final inner and outer diameters, and has a smaller diameter than the final inner and outer diameters and an axial thickness greater than the final axial thickness. A second intermediate product (W3) having a thick bottomed annular shape is formed, and the second intermediate product (W3) is formed.
The bottom (W3 ') of 3) is punched out with a punch (6) and a die (7), and has a smaller diameter than the final inner and outer diameters and an axial thickness greater than the final axial thickness. It is configured to form three intermediate products (W4).

[0009] As shown in FIG.
Forming roll (8) formed on the inner peripheral surface with the same shape as the outer peripheral shape of the fourth intermediate product (W5) and supported rotatably.
A mandrel (9) formed on the outer peripheral surface to have the same shape as the inner peripheral shape of the fourth intermediate product (W5) and rotatably and slidably supported in the radial direction; and a mandrel (9). And a pair of mandrel receiving rolls (10) and (10) that slide in a radial direction through a pressure applying means (not shown), and a gap between the forming roll (8) and the mandrel (9). Third
The intermediate product (W4) is pinched, and in this state, the mandrel (9) is radially moved by the mandrel receiving rolls (10) and (10) while rotating the forming roll (8) to contact and rotate the third intermediate product (W4). To the third intermediate product (W
The third intermediate product (W4) is ring-rolled between the forming roller (8) and the mandrel (9) by applying a nip pressure in the radial direction to 4), and has a diameter slightly smaller than the final inner and outer diameters. 4th thickness is slightly thicker than the final axial thickness
An intermediate product (W5) is formed.

As shown in FIG. 4, the above-mentioned oscillating rolling machine has a pressure forming surface (11a) that matches the final outer shape.
A pressure forming die (11) installed so as to be able to move up and down through a pressure applying means (not shown), and a conical pressing surface (12)
and a punch (12) having a central axis inclined at an angle to the central axis of the pressure forming die (11) and rotating while swinging on a circumference. Intermediate product (W5)
Is supplied into the pressing die (11), and the punch (1) is supplied.
2) is rotated while oscillating on the circumference, and in this state, the pressure forming die (11) is raised and the fourth intermediate product (W5) is rotated.
Is pressed against the pressing surface (12a) of the punch (12), the punch (12) partially places the fourth intermediate product (W5) on the pressing surface (11a) of the pressing die (11). Pressure is applied sequentially in the circumferential direction while applying pressure, whereby the pressure rolling surface (11a) of the pressure forming die (11) is rolled into the fourth intermediate product (W5), and the hypoid tooth (G) is formed. It is configured to form a fifth intermediate product (W6) that is formed by toothing.

As shown in FIG. 5, the punching machine has a die (13) having an inner shape corresponding to the final outer shape.
And a punching punch (14) having the same diameter as the final inner diameter. By supplying the fifth intermediate product (W6) into the die (13) and pressing the punching punch (14), the punching punch (14) is obtained. 5) formed at the time of tooth forming.
The burrs (W6 ') of the intermediate product (W6) are punched out and cold-coined to form a final product (7).

The method for manufacturing a hypoid ring gear according to the present invention is characterized in that the thickness of the first intermediate product (W2) is smaller than the final inner and outer diameters and the axial thickness is smaller than the final axial thickness. A second intermediate product (W3) having a thick bottomed annular shape is formed, and the bottom portion (W3 ′) of the second intermediate product (W3) is smaller in diameter than the final inner and outer diameters and has a final axial thickness. After punching out in a state thicker than the axial thickness of the product, ring rolling is used to produce a product with a slightly smaller diameter than the final inner and outer diameters and a slightly thicker axial thickness than the final axial thickness. 4 intermediate products (W5)
, A large forging press is not required, and equipment costs can be reduced. Moreover, the pressure forming surface (11) of the pressure forming die (11) is added to the fourth intermediate product (W5).
a) is sequentially pressurized in the circumferential direction while partially pressurizing the pressure rolling surface (11a) of the pressure forming die (11).
Is rolled into a fourth intermediate product (W5) to form the hypoid teeth (G) in a protruding manner, so that the equipment cost can be reduced as compared with the conventional gear cutting with two Gleason gear cutting machines. In addition, the running cost can be reduced by improving the material yield and shortening the processing time.

Since the hypoid ring gear manufactured by the manufacturing method of the present invention is formed by swing rolling to form the hypoid teeth (G), the hypoid teeth (G) are formed.
A tooth flow gland was formed along the tooth surface, and the tooth surface strength was remarkably improved as compared with that obtained by cutting. As a result, a large load can be transmitted with a small hypoid gear,
The size of the differential can be reduced. In addition, the processing time can be reduced and the running cost can be reduced as compared with a gear cut by a Gleason gear cutting machine.

[0014]

As described above, according to the present invention,
It is possible to provide a method of manufacturing a hypoid ring gear that can reduce equipment costs and running costs and minimize manufacturing costs, and improve the surface strength of hypoid teeth to reduce the size of the differential. Can be provided.

[Brief description of the drawings]

FIG. 1 is a process explanatory view showing a method for manufacturing a hypoid ring gear for differential of the present invention.

FIG. 2 is a schematic explanatory view of a forging press according to the present invention.

FIG. 3 is a schematic explanatory view of a rolling machine according to the present invention.

FIG. 4 is a schematic explanatory view of an oscillating rolling machine according to the present invention.

FIG. 5 is a schematic explanatory view of a punching machine according to the present invention.

FIG. 6 is a process explanatory view showing a method for manufacturing a conventional hypoid ring gear for differential.

[Explanation of symbols]

 W1 Round bar material W2 to W6 First intermediate product to Fifth intermediate product W7 Final product G Hypoid tooth 1 Induction heater 2 Upsetting punch 3 Die 4 Punch 5 Die 6 Punching punch 7 Die 8, 9 Edge roll 10 Receiving roll 11 Addition Pressure forming die 11a Pressure forming surface 12 Punch 13 Die 14 Punching punch

Claims (2)

[Claims] 1. A step of upsetting a round bar material heated to a predetermined temperature to form a disc-shaped first intermediate product, and die-forging the first intermediate product to form a final inner / outer diameter. Forming a bottomed annular second intermediate product having a smaller diameter than the final axial thickness and an axial thickness greater than the final axial thickness; and punching out the bottom of the second intermediate product from the final inner / outer diameter. Forming a bottomless annular third intermediate product having a small diameter and an axial thickness greater than the final axial thickness; and removing the scale by shot blasting the third intermediate product and then reducing the temperature to a predetermined temperature. Reheating and ring rolling to form a fourth intermediate product having a slightly smaller diameter than the final inner and outer diameters and a slightly thicker axial thickness than the final axial thickness. And forming the fifth intermediate product by shaping and rolling the fourth intermediate product to form hypoid teeth. And after normalizing and descaling the fifth intermediate product by normalizing shot blasting, punching out and cold-coining the inner burr of the fifth intermediate product formed at the time of the tooth forming to form a final product. And producing a hypoid ring gear for differential. 2. A hypoid ring gear for a differential manufactured by the method according to claim 1.